The band have pretty much disowned Into The Unknown, so I don't really think about it when I think of Bad Religion. I've youtube'd a few songs and they sound pretty dire, so I have no motivation to check it out. Maybe I will someday.
They certainly don't play any tracks from it, but the album shows a lot of the creativity the band had up their sleeve -- even if the results ended up somewhat strange. The album also resulted in the departure of two band members, which unquestionably shaped Bad Religion going forward. Of course it's not their best, but it's an important listen into Bad Religion history.
My favorite "thing" about Bad Religion is watching the music industry's production style, cost, and effort change over the course of three decades. Fourteen year olds can do more with a $300 laptop in 2013 than Bad Religion could do with their entire budget when their debut came out. As they gained label support, as production costs dropped, as the loudness wars took hold.. the results were generally a band playing the same style of music decades later but in a more polished form.
There are a lot of bands who have their own version of Into the Unknown these days, but it's not as noticeable with the super slick production that has become a standard for all genres.